Mitochondrial heteroplasmic variant has been increasingly recognized as a potential contributor to common complex diseases, yet its relationship with cardiometabolic disorders (CMDs) remains poorly understood. Leveraging deep whole-genome sequencing data from 16,882 participants across six multi-ancestry TOPMed cohorts, we systematically evaluated the associations between rare heteroplasmic variants and eight CMD traits, including body mass index (BMI), obesity, blood pressure, hypertension, blood glucose, diabetes, low-density lipoprotein (LDL), and hyperlipidemia. Using a previously developed statistical framework, we identified heteroplasmic variants according to three coding definitions and performed gene-based burden, SKAT, SKAT-O and ACAT-O tests within sixteen mitochondrial DNA (mtDNA) genes. We identified twelve significant gene-trait associations after Bonferroni correction, with consistent effect directions across coding definitions. The strongest association was observed between hyperlipidemia and heteroplasmic variants in CO1 gene (OR=0.28, 95% CI=(0.17, 0.46), p=3.4E-7) among EA (European Americans). Additional associations were detected for BMI, adjusted SBP (systolic blood pressure), BG (blood glucose), diabetes, and adjusted LDL. These findings highlight the contribution of heteroplasmic variation within mtDNA to cardiometabolic phenotypes and provide new insight into mitochondrial involvement in CMD pathophysiology.

Personality traits describe stable differences in how people think, feel and behave, and how they interact with and experience their social and physical environments1,2. Many questions remain unanswered about associations between DNA and personality traits, such as their robustness, their generalizability and the biological and social pathways through which they act. Here we meta-analyse data across 46 cohorts comprising 611,037 to 1.14 million participants with European-like and African-like genomes for genome-wide association studies (GWAS) of the Big Five personality traits (extraversion, agreeableness, conscientiousness, neuroticism and openness to experience), and data from up to 50,725 participants for within-family GWAS. We identify 1,260 lead genetic variants associated with personality, including 824 novel variants3. Common genetic variants explain a moderate 4.8-9.3% of the variance in measures of each trait, and 9.3-13.3% among instruments with typical measurement reliability. Genetic associations with personality are highly consistent but not identical across geography, reporter (self versus close other), age group and measurement instrument, and we find minimal spousal assortment for personality in recent history. In contrast to many other social and behavioural traits4,5, within-family GWAS and polygenic index analyses indicate that genetic associations with personality are minimally confounded by the shared family environment. Polygenic prediction, genetic correlation and Mendelian randomization analyses indicate that personality traits have widespread, potentially causal associations with consequential behaviours and life outcomes. Overall, we find that the genetic architecture of personality is robustly generalizable, minimally confounded and widely relevant to human experience.

The mitochondrial cascade hypothesis suggests that mitochondrial dysfunction plays an important role in the pathogenesis of Alzheimer’s disease dementia. Recent data have shown that mitochondrial DNA copy number (mtDNAcn) in human blood is associated with dementia risk and cognitive function, but which specific cognitive measures or domains are associated with mitochondrial dysfunction and whether this relationship is affected by health deterioration such as physical frailty or mitochondrial somatic mutations is not clear. We measured mtDNAcn and heteroplasmies using fastMitoCalc and MitoCaller, respectively, from UK Biobank Whole Genome Sequencing (WGS) data at study entry (2006-2010). Pre-frail/frail status was determined by the presence of slow gait, weight loss, low grip strength, exhaustion, or low physical activity. Cognitive function was assessed in a subset of participants (mean age=64.1,51.7% women, 97.0% White) on average 8.9 years after study entry, including processing speed via Digit Symbol Substitution Test (DSST)(n=13,940), attention via Trail Making Test (TMT) part A(n=13,482), executive function via delta TMT(n=13,428) and tower rearranging task(n=13,819), memory via paired associative learning task(n=14,094), and fluid reasoning via matrix pattern completion task(n=13,935). We examined the associations between mtDNAcn and cognitive measures using multivariate linear regression, adjusted for demographic factors, smoking status, follow-up time, measures related to mtDNAcn assessment, and Apolipoprotein E ε4 status. We then stratified the analysis by frailty status and levels of heteroplasmy load. Overall, more mtDNAcn was significantly associated with higher DSST (p=0.036) but not with other cognitive measures. After stratification by frailty status, mtDNAcn was associated with DSST, delta TMT, and paired associative learning in the pre-frail/frail participants only (p=0.047,0.007, and 0.044, respectively). After stratification by a median split of heteroplasmy load, mtDNAcn was associated with DSST and paired associative learning in those with higher heteroplasmy load (p=0.039 and 0.031, respectively). Results remained similar after excluding participants with dementia diagnosis (n=15). Higher mitochondrial DNA copy number from human blood is associated with higher cognition in specific measures. The associations with processing speed, executive function, and memory are prominent in individuals with health deterioration of physical frailty or high level of mtDNA heteroplasmy. Future studies are warranted to understand the biological underpinnings.

To improve health outcomes for COVID-19 (coronavirus disease 2019) patients, the factors that influence coronavirus genome variation need to be ascertained. The SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) genome is rich in predicted RNA secondary structures, particularly stem-loops (SLs) formed by intramolecular base pairing within palindromic sequences. We analyzed the NCBI Virus collection of SARS-CoV-2 genome sequences from COVID-19 individuals to map variants relative to SL structural elements. Point mutations in the SARS-CoV-2 genome, with a C-to-U transition bias, were over-represented in unpaired nucleotides and, more specifically, within the terminal loops of RNA SL structures. As the sole helicase encoded by SARS-CoV-2, Nsp13 may operate in the timely resolution of secondary RNA structures to facilitate SARS-CoV-2 RNA copying or processing. We characterized Nsp13 to resolve SARS-CoV-2 sequence-derived unimolecular RNA SL substrates and determined that it does so in a functionally cooperative manner. In addition to ATP, Nsp13 resolves the unimolecular RNA SL structure in the absence of nucleotide, in contrast to the strict ATP requirement for a bimolecular RNA forked duplex. We suggest a model in which a series of binary and ternary complex interactions of Nsp13 with nucleotide and/or RNA SL pose mechanistic implications for RNA SL resolution.

In this paper, we develop stochastic generalized functional regression models for association analysis at gene levels to analyze binary traits with sequencing genetic data in longitudinal genetic studies. Based on the theory of stochastic processes, we construct a variance-covariance structure to model the measurement variation and correlations of an individual's traits. Functional data analysis techniques are used to reduce high dimensionality of sequencing data and to draw useful information from the sequence data. It is shown that the proposed stochastic models control type I errors well, and have high power levels by intensive simulation studies. We test and refine the models and related software using real data sets from the Multi-Ethnic Study of Atherosclerosis (MESA). We investigate association between genes and hypertension status using the MESA data. Our research provides statistical methods and software to perform a gene-based association analysis of binary traits for sequence data in longitudinal studies.

Background: Brain iron in specific subcortical regions increases risk of dementia and Parkinson's disease (PD). Genetic and environmental factors affect iron deposition, but underlying mechanisms are unclear. Objective; Identify risk factors and diseases associated with brain iron; assess causality using genetics. Methods: 41,581 UK Biobank participants had MRI-estimated brain iron (QSM method) in five dementia or PD-associated subcortical regions (caudate, hippocampus, putamen, substantia nigra, thalamus). We investigated common risk factors (including adiposity, blood pressure, health behaviors, inflammation) and diseases observationally, using covariate-adjusted regression models, and genetically, with Mendelian randomization. Results: Participants diagnosed with Alzheimer's disease, PD, or other diseases had higher MRI-estimated brain iron. Anemia, osteoporosis, and hyperparathyroidism were associated with lower brain iron. Higher body mass index and blood pressure, smoking history, and self-reported meat consumption, increased brain iron. Hematological parameters, inflammatory and kidney biomarkers, and calcium, were also associated. Genetics support causal effects of depression, type-2 diabetes, and 7 other diseases with increased iron, but not Alzheimer's disease. Evidence supports a causal effect of osteoporosis on lower iron in the substantia nigra. We found causal associations between adiposity and proteins (including IL-6 receptor and transferrin receptor) on subcortical brain iron. Conclusions: We identified causal effects for liability to type-2 diabetes, depression, and other conditions, on subcortical MRI-estimated brain iron, but not to Alzheimer's disease, supportive of dementia as a consequence of brain iron deposition, not a cause. The role of adiposity reducing interventions on brain iron should be investigated. Relationships between brain iron, osteoporosis, calcium, and hyperparathyroidism warrant further investigation.

Personality traits describe stable differences in how individuals think, feel, and behave and how they interact with and experience their social and physical environments. We assemble data from 46 cohorts including 611K-1.14M participants with European-like and African-like genomes for genome-wide association studies (GWAS) of the Big Five personality traits (extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience), and data from 51K participants for within-family GWAS. We identify 1,257 lead genetic variants associated with personality, including 823 novel variants. Common genetic variants explain 4.8%-9.3% of the variance in each trait, and 10.5%-16.2% accounting for measurement unreliability. Genetic effects on personality are highly consistent across geography, reporter (self vs. close other), age group, and measurement instrument, and we find minimal spousal assortment for personality in recent history. In stark contrast to many other social and behavioral traits, within-family GWAS and polygenic index analyses indicate little to no shared environmental confounding in genetic associations with personality. Polygenic prediction, genetic correlation, and Mendelian randomization analyses indicate that personality genetics have widespread, potentially causal associations with a wide range of consequential behaviors and life outcomes. The genetic architecture of personality is robust and fundamental to being a human.

BACKGROUND:Growth differentiation factor 15 (GDF-15) levels are emerging as a candidate biomarker of aging. The present study aimed to: (1) characterize the association of GDF-15 with the continuum of arterial stiffening, assessed as carotid-femoral pulse wave velocity, as age increases; (2) determine the predictive role of serum GDF-15 levels on mortality; and (3) identify genetic determinants of serum GDF-15 levels. METHODS AND RESULTS:Serum levels of GDF-15 and established cardiovascular risk factors, including pulse wave velocity, were assessed in a large (4736 individual) Sardinian population. Serum levels of GDF-15, which can be reliably measured repeatedly over time, increase with age; are associated with a stiffer aorta; "mediate" a large proportion of the age-associated increase in arterial stiffness; pose risks because of their association with greater mortality; and are significantly associated with the variant rs11549407, which causes thalassemia major in homozygosity. CONCLUSIONS:Because of its consistent ability to predict functional and clinical outcomes, including all-cause mortality, we conclude that GDF-15 serum levels serve as a robust biomarker for the continuum from health to the emergence of clinical disease during aging and, subsequently, to the likelihood of mortality.

BACKGROUND:Iron overload is observed in neurodegenerative diseases, especially Alzheimer's disease (AD) and Parkinson's disease (PD). Homozygotes for the iron-overload (haemochromatosis) causing HFE p.C282Y variant have increased risk of dementia and PD. Whether brain iron deposition is causal or secondary to the neurodegenerative processes in the general population is unclear. METHODS:We analysed 39,533 UK Biobank participants of European genetic ancestry with brain MRI data. We studied brain iron estimated by R2* and quantitative susceptibility mapping (QSM) in 8 subcortical regions: accumbens, amygdala, caudate, hippocampus, pallidum, putamen, substantia nigra, and thalamus. We performed genome-wide associations studies (GWAS) and used Mendelian Randomization (MR) methods to estimate the causal effect of brain iron on grey matter volume, and risk of AD, non-AD and PD. We also used MR to test whether genetic liability to AD or PD causally increased brain iron (R2* and QSM). FINDINGS:In GWAS of R2* and QSM we replicated 83% of previously reported genetic loci and identified 174 further loci across all eight brain regions. Higher genetically predicted brain iron, using both R2* and QSM, was associated with lower grey matter volumes in the caudate, putamen and thalamus (e.g., Beta-putamenQSM: -0.37, p = 2*10-46). Higher genetically predicted thalamus R2* was associated with increased risk of non-AD dementia (OR 1.36(1.16;1.60), p = 2*10-4) but not AD (p > 0.05). In males, genetically predicted putamen R2* increased non-AD dementia risk, but not in females. Higher genetically predicted iron in the caudate, putamen, and substantia nigra was associated with an increased risk of PD (Odds Ratio QSM ∼ substantia-nigra 1.21(1.07;1.37), p = 0.003). Genetic liability to AD or PD was not associated with R2* or QSM in the dementia or PD-associated regions. INTERPRETATION:Our genetic analysis supports a causal effect of higher iron deposition in specific subcortical brain regions for Parkinson's disease, grey matter volume, and non-Alzheimer's dementia.

Though several studies demonstrated sex differences in behavior and functions of adult stem cell (ASC) populations, including neural, intestinal, musculoskeletal, and hematopoietic stem cells (HSCs), the extent to which sex affects age-associated alterations in ASC populations remains largely unknown. HSCs are responsible for lifelong production of all blood and immune cells, and as in other fields of medicine and biology, preclinical studies of HSC biology and aging have been performed predominantly in male mice. Therefore, sex-specific differences in the aging hematopoietic compartments are poorly defined.Thus, we sought to identify sex differences that may contribute to divergent aging phenotypes in C57BL/6 mice. We first cross-sectionally evaluated differences in overall hematopoietic system throughout aging and present unique aging profiles of the two sexes. Specifically, old males display a higher frequency of myeloid-biased and platelet-primed stem cells in the bone marrow and age-associated increase in platelet numbers in blood, whereas females do not. We next explored how aged HSC compartment contributed to sex-specific profiles using sex-matched/mismatched transplants, transcriptional analysis, and epigenetic profiling. We find that sex dimorphism in HSCs is driven by a combination of intrinsic and extrinsic factors, and that extramedullary hematopoiesis may be a significant contributor to age-related sex phenotypes. We also present hematopoietic parameters of both sexes throughout aging as a resource to characterize sex dimorphism of aging hematopoietic system to highlight key populations within the blood system that would and would not be appropriate for universal measurements at different age ranges.

Abstract Recent reports have shown that blood mitochondrial DNA copy number (mtDNAcn) is associated with dementia risk, but the biological underpinnings remain unclear. Identifying proteins that mediate this relationship may provide mechanistic insights. In the UK Biobank, we performed mediation analyses of 2,917 proteins via Olink platform in the association between mtDNAcn estimated using fastMitoCalc and future dementia diagnosis among 33,852 participants initially free of dementia (mean age=57 years). Over an average 13.2 years of follow-up, 891 participants (2.6%) developed all-cause dementia. We found 57 mediating proteins for all-cause dementia (FDR-p< 0.05), mostly from inflammation and cardiometabolic function panels and implicated in 24 pathways with top ranked pathways being TNFs binding to physiological receptors, coagulation system, plasma lipoprotein assembly/remodeling/clearance, degradation of the extracellular matrix, and activation of matrix metalloproteinases (p< 0.05). Three protein networks with more than 10 significant proteins were related to organismal injury and abnormality, hereditary disorders, cellular function and maintenance, post-translational modification, cell death and survival, and lipid metabolism. Of 57 mediating proteins for all-cause dementia, 4 proteins (TNFRSF11B, SMOC1, Fibronectin, and SMAD1) also mediated the relationship between mtDNAcn and cognitive impairment or dementia in the validation cohort of 593 Baltimore Longitudinal Study of Aging participants with available cross-sectional data (mean age=76.8 years, SomaScan, p< 0.05). These findings may suggest that proteins important for energy metabolism, neurotransmitter synthesis, lipid and glucose homeostasis, and immunity may underlie the relationship between mitochondrial dysfunction and dementia risk. Future longitudinal studies should further validate these findings and investigate longitudinal changes in proteins.

Iron overload is implicated in mitochondrial dysfunction. Some iron and mitochondria-related measures show sex differences. It is unclear whether mitochondrial DNA copy number (mtDNAcn) from blood associated with iron depositions in the brain or liver and whether the relationship differs by sex. In this population-based study, we find that among community-dwelling adults, lower mtDNAcn assessed in blood is associated with higher brain iron in basal ganglia and hippocampus and more liver fat, and not with brain volumes or liver iron. Interestingly, the association between mtDNAcn and brain iron in basal ganglia is prominent in men. Our observations lead to the hypothesis that mechanisms connecting mitochondrial dysfunction and iron overload may differ between brain and liver and differ by sex.

We rigorously assessed a comprehensive association testing framework for heteroplasmy, employing both simulated and real-world data. This framework employed a variant allele fraction (VAF) threshold and harnessed multiple gene-based tests for robust identification and association testing of heteroplasmy. Our simulation studies demonstrated that gene-based tests maintained an appropriate type I error rate at α=0.001. Notably, when 5% or more heteroplasmic variants within a target region were linked to an outcome, burden-extension tests (including the adaptive burden test, variable threshold burden test, and z-score weighting burden test) outperformed the sequence kernel association test (SKAT) and the original burden test. Applying this framework, we conducted association analyses on whole-blood derived heteroplasmy in 17,507 individuals of African and European ancestries (31% of African Ancestry, mean age of 62, with 58% women) with whole genome sequencing data. We performed both cohort- and ancestry-specific association analyses, followed by meta-analysis on both pooled samples and within each ancestry group. Our results suggest that mtDNA-encoded genes/regions are likely to exhibit varying rates in somatic aging, with the notably strong associations observed between heteroplasmy in the RNR1 and RNR2 genes (p<0.001) and advance aging by the Original Burden test. In contrast, SKAT identified significant associations (p<0.001) between diabetes and the aggregated effects of heteroplasmy in several protein-coding genes. Further research is warranted to validate these findings. In summary, our proposed statistical framework represents a valuable tool for facilitating association testing of heteroplasmy with disease traits in large human populations.

Alzheimer’s Disease (AD) is a complex polygenic neurodegenerative disorder. Its genetic risk’s relationship with all-cause dementia may be influenced by the plasma proteome. Up to 40,139 UK Biobank participants aged ≥ 50y at baseline assessment (2006–2010) were followed-up for ≤ 15 y for dementia incidence. Plasma proteomics were performed on a sub-sample of UK Biobank participants (k = 1,463 plasma proteins). AD polygenic risk scores (PRS) were used as the primary exposure and Cox proportional hazards models were conducted to examine the AD PRS-dementia relationship. A four-way decomposition model then partitioned the total effect (TE) of AD PRS on dementia into an effect due to mediation only, an effect due to interaction only, neither or both. The study found that AD PRS tertiles significantly increased the risk for all-cause dementia, particularly among women. The study specifically found that AD PRS was associated with a 79

Background Brain iron deposition is common in dementia, but whether serum iron is a causal risk factor is unknown. We aimed to determine whether genetic predisposition to higher serum iron status biomarkers increased risk of dementia and atrophy of grey matter. Methods We analysed UK Biobank participants clustered into European (N=451284), African (N=7477) and South Asian (N=9570) groups by genetic similarity to the 1000 genomes project. Using Mendelian randomisation methods, we estimated the association between genetically predicted serum iron (transferrin saturation [TSAT] and ferritin), grey matter volume and genetic liability to clinically defined dementia (including Alzheimer’s disease [AD], non-AD dementia, and vascular dementia) from hospital and primary care records. We also performed time-to-event (competing risks) analysis of the TSAT polygenic score on risk of clinically defined non-AD dementia. Results In Europeans, higher genetically predicted TSAT increased genetic liability to dementia (Odds Ratio [OR]: 1.15, 95% Confidence Intervals [CI] 1.04 to 1.26, p=0.0051), non-AD dementia (OR: 1.27, 95% CI 1.12 to 1.45, p=0.00018) and vascular dementia (OR: 1.37, 95% CI 1.12 to 1.69, p=0.0023), but not AD (OR: 1.00, 95% CI 0.86 to 1.15, p=0.97). Higher TSAT was also associated with increased risk of non-AD dementia in participants of African, but not South Asian groups. In survival analysis using a TSAT polygenic score, the effect was independent of apolipoprotein-E ε4 genotype (with adjustment subdistribution Hazard Ratio: 1.74, 95% CI 1.33 to 2.28, p=0.00006). Genetically predicted TSAT was associated with lower grey matter volume in caudate, putamen and thalamus, and not in other areas of interest. Discussion Genetic evidence supports a causal relationship between higher TSAT and risk of clinically defined non-AD and vascular dementia, in European and African groups. This association appears to be independent of apolipoprotein-E ε4.

Mitochondrial dysfunction is linked to physical impairment and dementia. Mitochondrial DNA copy number (mtDNAcn) from blood may predict cognitive decline and dementia risk, but the effect of somatic mutations or frailty is unknown. We estimated mtDNAcn using fastMitoCalc and microheteroplasmies using mitoCaller, from Whole Genome Sequencing (WGS) data. In 189,566 participants free of dementia at study entry (mean age = 56 ± 8), we examined the association between mtDNAcn and subsequent dementia diagnosis using Cox regression. Cognition was assessed in a subset on average 8.9 years later. We examined the associations between mtDNAcn and cognitive measures using multivariable linear regression, adjusted for demographic factors, mtDNAcn-related parameters, and apolipoprotein E ε4 status. We further stratified by frailty and microheteroplasmies. Over an average follow-up of 13.2 years, 3533 participants developed dementia. Each SD higher mtDNAcn (16) was associated with 4.2

Mobility impairment precedes Alzheimer’s disease (AD) and dementia. Potential mechanisms may involve mitochondrial dysfunction which is a hallmark of aging and links to both mobility impairment and brain health. In this study, we aimed to determine whether mitochondrial DNA copy number (mtDNA-CN), a blood-based marker related to mitochondrial function, would predict future dementia with and without the presence of early mobility impairment. In the UK Biobank, we estimated mtDNA-CN using fastMitoCalc from complete Whole Genome Sequencing data at study entry. Dementia diagnoses were ascertained from medical records, including AD and non-AD dementia. Early mobility impairment was defined as having slow walking pace by self-report at study entry. The absence of mobility impairment was defined as having steady average or brisk walking pace. In participants who were free of dementia at study entry, we examined the association between mtDNA-CN and future dementia with and without early mobility impairment using cox proportional hazard models, adjusted for age, sex, ethnicity, body mass index, apolipoprotein ε4 carrier status, assessment center, and technical covariates related to mtDNA-CN. Among 188,706 participants (mean age = 56±8 years, 55% women, 94% White), 13,821 reported slow walking pace at study entry and 2,564 developed dementia (1,085 AD, 1,479 non-AD dementia) over a mean follow-up of 12.5 years. After covariate adjustment, each standard deviation higher mtDNA-CN (i.e. 16) was marginally associated with a lower risk of any dementia (HR = 0.96, 95%CI: 0.91-1.00, p = 0.063). Among those who reported slow walking pace at study entry, each standard deviation higher mtDNA-CN was associated with a 12% lower risk of developing any dementia (HR = 0.88, 95%CI: 0.783-0.991, p = 0.034). There was a trend toward significance for non-AD dementia (HR = 0.87, 95%CI: 0.754-1.01, p = 0.065), and not for AD dementia (HR = 0.89, 95% CI: 0.727-1.09, p = 0.245). Among those without early mobility impairment, mtDNA-CN was not significantly associated with dementia (HR = 0.97, 95%CI: 0.92-1.02, p = 0.176). In a large sample of community-dwelling adults, higher mtDNA-CN is associated with a lower risk of developing dementia especially accompanied by early mobility impairment. Maintaining mitochondrial function in aging may protect against dementia that is preceded by mobility impairment.

Background The relationship between mitochondrial DNA copy number (mtDNA CN) and cardiovascular disease remains elusive. Methods and Results We performed cross‐sectional and prospective association analyses of blood‐derived mtDNA CN and cardiovascular disease outcomes in 27 316 participants in 8 cohorts of multiple racial and ethnic groups with whole‐genome sequencing. We also performed Mendelian randomization to explore causal relationships of mtDNA CN with coronary heart disease (CHD) and cardiometabolic risk factors (obesity, diabetes, hypertension, and hyperlipidemia). P<0.01 was used for significance. We validated most of the previously reported associations between mtDNA CN and cardiovascular disease outcomes. For example, 1‐SD unit lower level of mtDNA CN was associated with 1.08 (95% CI, 1.04–1.12; P<0.001) times the hazard for developing incident CHD, adjusting for covariates. Mendelian randomization analyses showed no causal effect from a lower level of mtDNA CN to a higher CHD risk (β=0.091; P=0.11) or in the reverse direction (β=−0.012; P=0.076). Additional bidirectional Mendelian randomization analyses revealed that low‐density lipoprotein cholesterol had a causal effect on mtDNA CN (β=−0.084; P<0.001), but the reverse direction was not significant (P=0.059). No causal associations were observed between mtDNA CN and obesity, diabetes, and hypertension, in either direction. Multivariable Mendelian randomization analyses showed no causal effect of CHD on mtDNA CN, controlling for low‐density lipoprotein cholesterol level (P=0.52), whereas there was a strong direct causal effect of higher low‐density lipoprotein cholesterol on lower mtDNA CN, adjusting for CHD status (β=−0.092; P<0.001). Conclusions Our findings indicate that high low‐density lipoprotein cholesterol may underlie the complex relationships between mtDNA CN and vascular atherosclerosis.

Senescent cells are beneficial for repairing acute tissue damage, but they are harmful when they accumulate in tissues, as occurs with advancing age. Senescence-associated extracellular vesicles (S-EVs) can mediate cell-to-cell communication and export intracellular content to the microenvironment of aging tissues. Here, we studied the uptake of EVs from senescent cells (S-EVs) and proliferating cells (P-EVs) and found that P-EVs were readily taken up by proliferating cells (fibroblasts and cervical cancer cells) while S-EVs were not. We thus investigated the surface proteome (surfaceome) of P-EVs relative to S-EVs derived from cells that had reached senescence via replicative exhaustion, exposure to ionizing radiation, or treatment with etoposide. We found that relative to P-EVs, S-EVs from all senescence models were enriched in proteins DPP4, ANXA1, ANXA6, S10AB, AT1A1, and EPHB2. Among them, DPP4 was found to selectively prevent uptake by proliferating cells, as ectopic overexpression of DPP4 in HeLa cells rendered DPP4-expressing EVs that were no longer taken up by other proliferating cells. We propose that DPP4 on the surface of S-EVs makes these EVs refractory to internalization by proliferating cells, advancing our knowledge of the impact of senescent cells in aging-associated processes.